Tire pressure indicator



Dec. 16, 1947.

M. A. I ACEY TIRE PRESSURE INDICATOR Filed May 22, 1945 INVENTOR. 1(026227 Ji lac e5. BY ZW Arron/vs Y0 Patented Dec. 16 1947 UNITED STATES PATENT OFFICE The present invention relates to new and useful improvements in tire pressure indicators, and more particularly to a device for indicating to the driver of a vehicle when one of the tires thereof drops below a certain predetermined pressure.

A further object of the invention is to provide an indicator embodying a signal lamp on the instrument panel of the vehicle and included in an electric circuit with a switch device carried by each of the wheels of the vehicle and arranged to be closed upon a predetermined deflation of the tires.

Another object of the invention is to provide adjustable means associated with the device and in which the closing movement for the switch can be varied in accordance with a desired pressure condition.

Another object of the invention is to provide a device of this character of simple and practical construction, which is eflicient and reliable in operation, relatively inexpensive to manufacture and install in operative position on the wheel of a vehicle, and which is otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawing forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a transverse sectional view of a vehicle wheel showing the tire-deflation signalling device mounted thereon.

Figure 2 is an enlarged vertical sectional view of the signalling device.

Figures 3 and 4 are transverse sectional views taken respectively on the lines 3-3 and 44 of Figure 2.

Referring now to the drawing in detail, wherein for the purpose of illustration I have shown a preferred embodiment of the invention, the numeral 5 designates a vehicle wheel of conventional construction and including a hub 6 and rim 1 on which a pneumatic tire 8 is mounted, the tire including the usual inner tube 9.

A switch housing I is secured at the outer surface of the wheel to the inside of the rim 1, the rim having an opening ll through which a screw l2 freely works, the screw having a pad I3 secured at its outer end and positioned at the side of the inner tube 9 adjacent the rim, the pad conforming to the curvature of the inner tube and the tire casing.

The screw I2 is threaded upwardly into the 2 lower end of a rack bar I 4 which is slidably mounted in a passage l5 in the housing ID, the upper end of the rack bar being formed with a head l6 working in a chamber I! in the upper portion of the housing and yieldably urged downwardly by means of a coil spring i8 positioned in the chamber above the head and secured in position in the chamber by means of a threaded plug IS, the plug providing means for adjusting the tension of the spring.

One edge of the rack bar I 4 is formed with rack teeth 20 engaging a pinion 2| journaled on a pin 22 in the housing It, the pinion also engaging the teeth 23 of a second rack bar 24 slidably mounted in a chamber 25 in the housing and at a side of the pinion opposite from the rack bar M.

The rack bar 24 extends upwardly through the top of the housing and a metallic bristle brush 2B is threaded in the upper end of said bar. A coil spring 28 is also positioned in the chamber 25 behind the rack bar 24 to assist in the outward movement thereof.

A contact arm 21 is secured to the outer end of the hub 6 and extends longitudinally inwardly thereof at one side of the hub and in the path of the outward sliding movement of the brush 26 on the outer end of the rack bar 24, the bristles of the brush assisting to keep the contact clean The contact arm 21 is connected by an insulated wire 30 to an insulated brush 3| carried by a metal band 32 attached to the wheel hub 6. The brush 3| is in contact with an armature disk 33 carried by the wheel, the positive wire 35 from the lamp being connected to the disk 33 by means of a binding post 36.

In the operation of the device, when the tire 8 is inflated at a normal pressure, the inner tube 9 will force the pad l3 against the rim 1, thereby maintaining the rack bar It upwardly in the housing l0 against the tension of the spring l8.

Upon a decrease in the pressure of the tire, the spring l8 will force the rack bar l4 downwardly, as shown in Figure 2 of the drawing, or radially outwardly with respect to the wheel, thereby rotating the pinion 2| and causing a radial inward movement of the rack bar 24 so as to move the brush 25 into contact with the contact arm 21.

Accordingly, by connecting the contact arm 21 with an electric lamp (not shown) at the instrument panel of the vehicle, in a conventional manner, the lamp will be energized upon a closing of the switch composed of the brush 26 and contact arm 21 and thus indicate to the driver a predetermined decrease in the pressure of the tire. The housing In is provided with a removable plate Illa by means of which the rack bar 24 may be ad- J'usted relative to the pinion 2 I.

It will be understood that each of the four wheels of the vehicle is provided with one of the switch mechanisms heretofore described, and including a lamp mounted on the instrument panel so that a deflation signal for each of the tires will be provided.

It is believed the details of construction, advantages and-mannerv of use of the device will be readily understood from the foregoing without further detailed explanation.

Having thus described the invention, whatds claimed is:

1. A tire deflation indicator comprising a stationary contact adapted for attaching tolthe-rhub of a vehicle wheel, said wheel including a pneumatic tire mounted thereon and provided with an inner tube, a housing carried by the wheel, a spring-loaded pad yieldably held in engagement with the inner tube,.a contact brush, and rack and. pinion means connecting the brush with the pad and openableuponadeflating movement of -thetire to movethe brush toward the stationary contact.

2. A tiredeflationindicator comprising a stationary contact adapted for attaching tothe hub ,of a vehicle .wheel, said wheel including a.pneumaticztire mounted thereon andv provided with an inner tube, a housing carried bythe wheel, a pair ,of rack bars slidably mounted in parallel relation in the housing, a pinion operatively connecting the rack. bars for opposite-movement, a pad carried by, one of the rack bars and disposed in engagement with the inner tube,- spring meansurg ing the pad againstthe inner tube, and a contact brush carriedby the other rack bar and movable ,toward the stationary contact upon apredetermined deflating movement of the tire.

3. A tire defiatingindicator comprising: a sta-- 4 .forcing the pad against'the inner tube, and a I contact brush carried by the other of said rack bars and movable toward the stationary contact --.upon a predetermined deflating movement of the -,-tire.

4. A'tire'defiating indicator comprising a staztionary contact adapted for attaching to the hub tionary contact adapted for attaching to the hub of a vehicle wheel, said wheel including a pneumatic tire mounted thereon and provided with Hana-inner tube, a housing carried by the Wheel, a

pair of rack bars slidably mounted in parallel relation in the housing, a pinion operatively connecting the rack bars for opposite movement, a padcarriedby one of the rack bars and disposed v in engagementwiththe inner tube, a coil spring behind said one rack bar for urging thepad against the inner tube, means for adjusting the tension of said coil spring, and a contact brush carried by the other of said rack bars and movable'toward the stationary contact upon a predetermined deflating movement of the tire.

MOLAN .A. LACEY.

' REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES-PATENTS Number Name Date 2,090,184 Card Aug. 17, 1937 2,147,512 .Asanuma d; Feb; 14, 1939 2,199,032 Stoddard ,Apr., 30, 1940 

